This Invention relates generally to gaseous-material evacuation systems and more particularly to such systems having filters for cleaning evacuated gases.
This invention has uses in the area of waste disposal, such as in devices and systems for evacuating aerosol cans, and other containers of pressurized gases and residue contents.
Pressurized aerosol cans, and other pressurized containers, have widespread usage in homes and industry. It has long been recognized that improper disposal of such containers constitutes a safety hazard in that excessive external heat and/or pressure can cause them to explode if they have not been relieved of internal pressure. Similarly, the release of contents, both propellant gases and dangerous residue materials, from such containers often damages the environment.
Due to these hazards, the Environmental Protection Agency (EPA), an agency of the U.S. Government, regulates disposal of pressurized containers as well as their contents for industries. These regulations mandate that certain businesses and industries must puncture all pressurized containers prior to their disposal. Further, these regulations require that certain contents of pressurized containers be captured and disposed of in particular manners. Depending upon the natures of such contents, disposal methods can involve permanent disposal through incineration, landfills or other means; treatment and permanent disposal; treatment and recycling; and treatment and reclamation for a new use. An example of reclamation would be recovering a solvent contained in waste paint for use as a fuel. But, whichever disposal method is used, the EPA requires many industries to relieve the pressure in pressurized containers prior to transporting them for disposal.
In addition to the above requirements of the EPA, many states within the United States and countries outside the United States have requirements similar to, or even stricter than, those of the EPA. For example, California closely regulates release of gases into the atmosphere. In this respect, California considers some propellants used in aerosol cans to be contaminants, particularly when they contain small aerosolized particles of materials, such as insecticides, paints and the like, which were in the aerosol cans.
A number of US Patents to Michael Campbell describe systems for evacuating gaseous materials from aerosol containers and other types of containers, see U.S. Pat. Nos. 5,163,585; 5,265,762; and 5,992,475. Most of these systems involve sealing a wall of an aerosol can on a seat, puncturing the can below the seat, and evacuating the contents of the can into a drum.
A widely used device for piercing pressurized containers is described in U.S. Pat. No. 5,265,762 to Campbell et al. This Campbell et al. patent describes a puncturing device for aerosol containers which includes an elongated tubular housing having male threads at a second end for being screwed into a first, or large, bung-plug hole (bunghole) of an off-the-shelf drum, such as a 15, 30 or 55 gallon drum. An aerosol can to be disposed of is inserted into a first opening at a first end of the cylindrical housing, nozzle-end-first, until a shoulder of the aerosol can engages a sealing shoulder seat in the elongated tubular housing. A puncturing member, as part of a mechanism mounted to the side of the housing, is driven through the housing to create a puncture opening in the aerosol can below the sealing shoulder seat. Propelling gas and residue material are driven from the aerosol can, by pressure of the propellant gas, through the puncture opening and through the second end opening of the housing into the drum. The sealing shoulder seat prevents the propellant gas and residue from retro-movement toward the first end opening of the housing (which opens to the environment) and ensures that these materials go into the drum.
Campbell et al (U.S. Pat. No. 5,265,762) also describes a filter screwed into a second, small, bunghole of the drum for filtering propellant gases escaping from the second bunghole of the drum to the environment for cleaning escaping gaseous vapors of atmosphere-harmful materials.
Other patents which describe devices and systems relating to the system described in Campbell et al (U.S. Pat. No. 5,265,762) include U.S. Pat. No. 3,358,883 to Loe; U.S. Pat. No. 3,828,976 to Sidelinker; 3,926,340 to Tygenhof; U.S. Pat. No. 4,349,054 to Chipman et al; U.S. Pat. No. 4,407,341 to Feldt et al; U.S. Pat. No. 5,114,043 to Collins, Jr.; U.S. Pat. No. 5,181,462 to Isaac; U.S. Pat. No. 5,271,437 to O""Brien et al; U.S. Pat. No. 5,284,997 to Spearman et al; U.S. Pat. No. 5,309,956 to Hajma; and U.S. Pat. No. 5,365,982 to O""Neill.
U.S. Pat. No. 5,992,475 to Campbell discloses a spring-activated check valve at the second end of the tubular wall of the housing with a spring-activated valve poppet positioned at the second end for opening and closing in response to pressure. Basically this check valve opens to allow propellant gases to escape from the punctured aerosol cans into the drum and then closes to prevent retrograde movement of the gases from the drum back through the piercing-device housing once the cans are removed. U.S. Pat. No. 5,181,462 to Issac also describes a similar valve.
Although these prior-art devices prevent retrograde movement of unfiltered gases through the piercing-device housing back to atmosphere, they do not prevent continuous flow of gases thorough the filter from the small bunghole when cans are not being evacuated. Such continuous flow of gaseous materials through the filter to atmosphere, even when cans are not being evacuated, is undesirable because personnel standing near the drum containing evacuated residue and gases are not aware that dangerous gases are being continually released. In this regard, when cans are being evacuated, personnel are aware that dangerous gases are being released and take necessary precautions. However, when cans are not being evacuated, personnel are not aware of such release and do not take precautions. For example, one might smoke a cigarette close to an unused evacuation drum, thereby possibly igniting gases escaping from the drum through the filter. For this reason, it is desirable that evacuation systems become xe2x80x9cclosed systemsxe2x80x9d when they are not being actively used for evacuation, and some regulations even promote such xe2x80x9cclosed systemsxe2x80x9d.
Thus, it is an object of this invention to provide a device for allowing desired easy flow of evacuated gaseous materials through a filter of an evacuation system when the evacuation system is being actively use for evacuation, but for stopping such flow when gaseous materials are not being actively evacuated.
According to principles of this invention a gaseous-material evacuation system includes a filter assembly with a housing containing filter material with a porous filter member at a downstream side of the filter material. The filter assembly includes a valve with a movable valve member for moving along a path of gas flow and having breadth area dimensions that are at least as great as those of a downstream side of the porous filter member through which pressurized gaseous materials flow. In a preferred embodiment, a coil spring member presses the movable valve member evenly against the porous filter member, thereby stopping gaseous flow, but yields evenly when gaseous materials are driven through the filter by a predetermined pressure. The valve member is mounted in a sub-chamber of the housing containing the filter material, which is a single-piece housing member, and which forms a seat for the movable valve member.